U.S. patent application number 14/583996 was filed with the patent office on 2017-03-02 for cooling systems for high mach applications.
The applicant listed for this patent is Rolls-Royce Corporation. Invention is credited to Igor Vaisman.
Application Number | 20170058773 14/583996 |
Document ID | / |
Family ID | 52347129 |
Filed Date | 2017-03-02 |
United States Patent
Application |
20170058773 |
Kind Code |
A1 |
Vaisman; Igor |
March 2, 2017 |
COOLING SYSTEMS FOR HIGH MACH APPLICATIONS
Abstract
A cooling system for an aircraft includes an air intake, a heat
exchanger configured to receive air passing into the air intake
when the aircraft is operating at Mach speed, and configured to
receive compressed refrigerant from a first compressor at a first
pressure, an evaporator positioned within the aircraft and
configured to receive heated air from a compartment within the
aircraft, at least one of an expansion device and an expansion
machine, and the compressed refrigerant rejects heat in the heat
exchanger to the air, expands in the at least one of the expansion
device and the expansion machine, and receives heat in the
evaporator from the heated air.
Inventors: |
Vaisman; Igor; (Carmel,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rolls-Royce Corporation |
Indianapolis |
IN |
US |
|
|
Family ID: |
52347129 |
Appl. No.: |
14/583996 |
Filed: |
December 29, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61921864 |
Dec 30, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02C 7/16 20130101; Y02T
50/50 20130101; F25B 2400/14 20130101; F25B 9/008 20130101; F25B
49/02 20130101; F25B 2309/005 20130101; F25B 1/10 20130101; F25B
40/00 20130101; Y02T 50/56 20130101; F25B 2600/2501 20130101; F25B
2309/061 20130101; F25B 11/04 20130101; F25B 2400/0411 20130101;
B64D 13/06 20130101; F25B 6/04 20130101 |
International
Class: |
F02C 7/16 20060101
F02C007/16 |
Claims
1. A cooling system for an aircraft, comprising: an air intake; a
first heat exchanger configured to receive air passing into the air
intake when the aircraft is operating at Mach speed, and configured
to receive compressed refrigerant from a first compressor at a
first pressure; an evaporator positioned within the aircraft and
configured to receive heated air from a compartment within the
aircraft; at least one of an expansion valve and a turbine; and the
compressed refrigerant rejects heat in the first heat exchanger to
the air, expands in the at least one of the expansion valve and the
turbine, and receives heat in the evaporator from the heated air;
wherein the at least one of the expansion valve and the turbine
further comprise: a first turbine configured to provide a first
power, and output the refrigerant to the first compressor; a second
turbine coupled to the first turbine via a shaft, wherein the
second turbine provides a second power to the first turbine, and
output the refrigerant to the first compressor; and an expansion
valve configured to receive refrigerant from the first heat
exchanger and expand the refrigerant to provide expanded
refrigerant to the evaporator.
2. The cooling system of claim 1, wherein the compartment is heated
at least with human body heat.
3. The cooling system of claim 1, wherein the cooling system
includes both the turbine and the expansion valve arranged in
parallel with one another, and further comprising a plurality of
valves that direct the refrigerant through: the expansion valve
during a sub-critical operation; and turbine during a super
critical operation.
4. The cooling system of claim 1, comprising a second compressor
configured to compress the refrigerant to a second pressure that is
lower than the first pressure, pass the refrigerant to a second
heat exchanger that is configured to receive the air passing into
the air intake when the aircraft is operating at the Mach speed,
and pass the refrigerant to the first compressor.
5. The cooling system of claim 1, wherein the refrigerant is
maintained wholly in a super critical mode from the first heat
exchanger through the turbine.
6. (canceled)
7. The cooling system of claim 1, further comprising a second
compressor configured to receive refrigerant from the first
compressor and at the first pressure, after having passed through a
second heat exchanger, and output the refrigerant at a second
pressure that is greater than the first pressure.
8. A method of operating a cooling system, the method comprising:
passing air, from an air intake in an aircraft that is operable at
Mach speed, to a first heat exchanger; receiving refrigerant in the
first heat exchanger from a first compressor and at a first
pressure; expanding the refrigerant from the first heat exchanger
in at least one of an expansion valve and an turbine; receiving
refrigerant from the at least one of the expansion valve and the
turbine in an evaporator that receives heated air from a
compartment of the aircraft; and rejecting heat in the first heat
exchanger to the air; wherein the at least one of the expansion
valve and the turbine further comprise: a first turbine configured
to provide a first power, and output the refrigerant to the first
compressor; a second turbine coupled to the first turbine via a
shaft, wherein the second turbine provides a second power to the
first turbine, and output the refrigerant to the first compressor;
and an expansion valve configured to receive refrigerant from the
first heat exchanger and expand the refrigerant to provide expanded
refrigerant to the evaporator.
9. The method as claimed in claim 8, wherein the compartment is
heated at least with human body heat.
10. The method as claimed in claim 8, wherein the cooling system
includes both the turbine and the expansion valve arranged in
parallel with one another, and further comprising operating a
plurality of valves that direct the refrigerant through: the
expansion valve during a sub-critical operation; and the turbine
during a super critical operation.
11. The method as claimed in claim 8, comprising: compressing the
refrigerant to a second pressure that is lower than the first
compressor in a second compressor; passing the refrigerant to a
second heat exchanger that is configured to receive the air passing
into the air intake when the aircraft is operating at the Mach
speed; and passing the refrigerant to the first compressor.
12. The method as claimed in claim 8, further comprising
maintaining the refrigerant wholly in a super critical mode from
the first heat exchanger through the turbine.
13. (canceled)
14. The method as claimed in claim 8, further comprising a second
compressor configured to receive refrigerant from the first
compressor and at the first pressure, after having passed through a
second heat exchanger, and output the refrigerant at a second
pressure that is greater than the first pressure.
15. An aircraft comprising: an air intake; and a cooling system for
the aircraft, the cooling system comprising: a first heat exchanger
configured to receive air passing into the air intake when the
aircraft is operating at Mach speed, and configured to receive
compressed refrigerant from a first compressor at a first pressure;
an evaporator positioned within the aircraft and configured to
receive heated air from a compartment; at least one of an expansion
valve and a turbine; and the compressed refrigerant rejects heat in
the first heat exchanger to the air, expands in the at least one of
the expansion valve and the turbine, and receives heat in the
evaporator from the heated air; wherein the at least one of the
expansion valve and the turbine further comprise: a first turbine
configured to provide a first power, and output the refrigerant to
the first compressor; a second turbine coupled to the first turbine
via a shaft, wherein the second turbine provides a second power to
the first turbine, and output the refrigerant to the first
compressor; an expansion valve configured to receive refrigerant
from the first heat exchanger and expand the refrigerant to provide
expanded refrigerant to the evaporator; and a second compressor
configured to receive refrigerant from the first compressor and at
the first pressure, after having passed through a second heat
exchanger, and output the refrigerant at a second pressure that is
greater than the first pressure.
16. The aircraft of claim 15, wherein the compartment is a
compartment of the aircraft that is heated at least with human body
heat.
17. The aircraft of claim 15, wherein the cooling system includes
both the turbine and the expansion valve arranged in parallel with
one another, and further comprising a plurality of valves that
direct the refrigerant through: the expansion valve during a
sub-critical operation; and the turbine during a super critical
operation.
18. The aircraft of claim 15, comprising a second compressor
configured to compress the refrigerant to a second pressure that is
lower than the first pressure, pass the refrigerant to a second
heat exchanger that is configured to receive the air passing into
the air intake when the aircraft is operating at the Mach speed,
and pass the refrigerant to the first compressor.
19. The aircraft of claim 15, wherein the refrigerant is maintained
wholly in a super critical mode from the first heat exchanger
through the turbine.
20. (canceled)
21. A cooling system for an aircraft, comprising: an air intake; a
first heat exchanger configured to receive air passing into the air
intake when the aircraft is operating at Mach speed, and configured
to receive compressed refrigerant from a first compressor at a
first pressure; an evaporator positioned within the aircraft and
configured to receive heated air from a compartment within the
aircraft; at least one of an expansion valve and a turbine; and the
compressed refrigerant rejects heat in the first heat exchanger to
the air, expands in the at least one of the expansion valve and the
turbine, and receives heat in the evaporator from the heated air; a
suction accumulator positioned to receive refrigerant from the
evaporator; and a recuperative heat exchanger positioned to
exchange heat between: 1) the refrigerant before it passes into the
expansion valve; and 2) the refrigerant from the suction
accumulator.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 61/921,864, filed Dec. 30, 2013, the contents of
which are hereby incorporated in their entirety.
FIELD OF TECHNOLOGY
[0002] An improved system and method of operating a cooling system
in an aerospace application is disclosed, and more particularly, an
improved system and method of operating the cooling system includes
operating in a high-mach environment.
BACKGROUND
[0003] It has become increasingly desirable to improve cooling
systems in aerospace applications. Typically, cooling systems
provide air conditioning, refrigeration and freezer services, and
the like for commercial and other aerospace systems. In general,
various known options are available for providing cooling, but such
options have drawbacks that limit the design options for aerospace
applications.
[0004] To accommodate the wide range of possible ambient operating
conditions of the aircraft, cooling systems for aerospace
applications often use a gas-based system. That is, typical cooling
systems include a relatively bulky and low efficiency gas-based
system in order to cover the range of conditions that can be
experienced during aircraft operation. Such systems include an
ability to reject heat during operation to complete the
thermodynamic cycle. However, some aircraft operate at above Mach
1, or the speed of sound, in which case the ability to reject heat
may be limited due to the frictional component that can cause
heating of air that may be used to reject heat.
[0005] Thus, cooling systems have been developed to provide
alternatives for heat rejection during high Mach aircraft
operation. One known option uses fuel or thermal storage units for
cooling as high Mach heat sinks That is, a fuel or other thermal
storage unit may be provided, to which heat may be rejected during
operation of an aircraft at high Mach speeds. However, fuel storage
units have limited capacity and limited operational time. And, as
fuel is consumed, the reservoir to which the heat is rejected is
reduced in volume, providing limited options for long duration
flights.
[0006] Thus, there is a need to improve cooling in aircraft for
high Mach operation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] While the claims are not limited to a specific illustration,
an appreciation of the various aspects is best gained through a
discussion of various examples thereof Referring now to the
drawings, exemplary illustrations are shown in detail. Although the
drawings represent the illustrations, the drawings are not
necessarily to scale and certain features may be exaggerated to
better illustrate and explain an innovative aspect of an example.
Further, the exemplary illustrations described herein are not
intended to be exhaustive or otherwise limiting or restricted to
the precise form and configuration shown in the drawings and
disclosed in the following detailed description. Exemplary
illustrations are described in detail by referring to the drawings
as follows:
[0008] FIG. 1A is an illustration of a gas turbine engine employed
in an aircraft and employing the improvements described herein;
[0009] FIG. 1B is a side view of an aircraft having a RAM air
intake;
[0010] FIG. 2 illustrates exemplary thermodynamic operation of a
cooling system between an air heat rejection temperature and an
ambient heat absorption temperature;
[0011] FIG. 3 illustrates an exemplary cooling system having one
compression loop;
[0012] FIG. 4 illustrates an exemplary cooling system having two
compression loops;
[0013] FIG. 5 illustrates an exemplary cooling system for only
super critical operation;
[0014] FIG. 6 illustrates a system having two expansion loops for
providing augmented power to extend the temperature differential in
the cooling system; and
[0015] FIG. 7 illustrates a system having two expansion loops for
providing augmented power to extend a temperature differential
across which the cooling system may operate, while augmenting
expansion capability.
DETAILED DESCRIPTION
[0016] An exemplary cooling system for an aircraft application is
described herein, and various embodiments thereof A cooling system
for an aircraft includes an air intake, a heat exchanger configured
to receive air passing into the air intake when the aircraft is
operating at Mach speed, and configured to receive compressed
refrigerant from a first compressor at a first pressure, an
evaporator positioned within the aircraft and configured to receive
heated air from a compartment within the aircraft, at least one of
an expansion device and an expansion machine, and the compressed
refrigerant rejects heat in the heat exchanger to the air, expands
in the at least one of the expansion device and the expansion
machine, and receives heat in the evaporator from the heated
air.
[0017] Another exemplary illustration includes a method of
operating a cooling system that includes a method of operating a
cooling system. The method includes passing air, from an air intake
in an aircraft that is operable at Mach speed, to a first heat
exchanger, receiving refrigerant in the first heat exchanger from a
first compressor and at a first pressure, expanding the refrigerant
from the heat exchanger in at least one of an expansion device and
an expansion machine, receiving refrigerant from the at least one
of the expansion device and the expansion machine in an evaporator
that receives heated air from a compartment of the aircraft, and
rejecting heat in the heat exchanger to the air.
[0018] Figure lA illustrates a schematic diagram of a gas turbine
machine 10 that is a primary mover or thrust source for an
aircraft, utilizing the improvements disclosed herein. The turbine
machine 10 includes a primary compressor 12, a combustor 14 and a
primary turbine assembly 16. A fan 18 includes a nosecone assembly
20, blade members 22 and a fan casing 24. The blade members 22
direct low pressure air to a bypass flow path 26 and to the
compressor intake 28, which in turn provides airflow to compressor
12. Components of FIG. 1 generally correspond to components of an
aircraft engine, and air intake to the engine, such as bypass air
26 may be used to reject heat to.
[0019] FIG. 1B illustrates an aircraft 40 that includes an
exemplary RAM air intake 50, which, in an alternative example, may
be employed in cooling systems, such as exemplary cooling systems
described herein. A RAM-air intake is any intake design which uses
the dynamic air pressure created by vehicle motion to increase the
static air pressure inside of the intake manifold on an engine,
thus allowing a greater mass flow through the engine and hence
increasing engine power. The RAM air intake works by reducing the
intake air velocity by increasing the cross sectional area of the
intake ducting. When gas velocity goes down the dynamic pressure is
reduced while the static pressure is increased. The increased
static pressure in a plenum chamber has a positive effect on engine
power, both because of the pressure itself and the increased air
density this higher pressure gives.
[0020] As will be described, air such as bypass air 26 or RAM air
from intake 50 of aircraft 40 is used to cool a refrigerant for a
compartment within aircraft 40. That is, when aircraft 40 is
operating above Mach or at high Mach (such as Mach 3 and above, for
example), incoming air is typically relatively hot. For instance,
at Mach 1, stagnation temperature is approximately 360 K
(195.degree. F.). As another example, at Mach 3 the stagnation
temperature is approximately 850 K (1070.degree. F.). And, as yet
another example, at Mach 5 the stagnation temperature is
approximately 1820 K (2800.degree. F.). Thus, to reject heat at
such relatively high temperatures, the disclosed exemplary cooling
systems operate across a temperature differential that spans from a
rejection temperature that is above the air temperature at high
Mach, to a heat absorption temperature that is typically
approximately at ambient temperature. That is, the disclosed
cooling systems provide cooling, in one example, that provide
cooling at temperatures that are generally comfortable for human
occupants of the aircraft, such as 20.degree. C. In other examples
the cooling may be provided for cooling electronics or other
equipment that may generate heat at temperatures that are generally
at ambient, or ranging from approximately 20-60.degree. C.
[0021] To span the temperature differential between air
temperatures for heat rejection and the relatively low temperatures
for heat rejection (which may or may not be below the dome of a
two-phase region for CO.sub.2), the disclosed exemplary systems
operate in a fashion generally analogous to cryogenic systems. For
instance, a known cycle such as a Linde cycle operates in a regime
where a Joule-Thompson coefficient is positive, and liquefaction
occurs at extremely low temperatures. Another known cycle, such as
a Claude cycle, is applicable and operates in a regime when the
Joule-Thompson effect is negative. As such, known cryogenic systems
operate across a very wide temperature differential in order to
reject heat at ambient temperatures and absorb heat a low or
cryogenic temperatures.
[0022] An exemplary thermodynamic illustration 200 of a disclosed
exemplary system is shown in FIG. 2, which in one example includes
CO.sub.2 as the working fluid or refrigerant. Illustration 200
spans from a heat rejection temperature 202 to a heat absorption
temperature 204. When under the dome, heat absorption occurs 206 at
a temperature below heat absorption temperature 204. Compression
208 causes refrigerant temperature 210 in excess of heat rejection
temperature 202, and isenthalpic heat rejection occurs 212, at
which point 214 refrigerant expansion 216 occurs, resulting, in
this example, in a vapor outside the dome 218 and below heat
absorption temperature 204. Isenthalps 220 are included for
relative reference throughout cycle 222.
[0023] Referring to FIG. 3, an exemplary cooling system 300 is
illustrated. System 300 includes cooling air 302 that arrives from
an air intake, such as bypass air 26, which passes into a heat
exchanger or gas cooler 304. A refrigerant, such as CO.sub.2,
passes into 306 heat exchanger 304, and rejects heat 308 to inlet
air 302. Refrigerant passes to an expansion device 310, passing
through recuperative heat exchangers 314, 316. In one example, an
optional recuperative heat exchanger 312 may be included for
additional heat recovery. When reaching expansion device 310,
refrigerant expands and passes to a heat exchanger or evaporator
318. The recuperative heat exchangers typically result in a
minimized temperature difference between streams at the hot end. A
heat load 320 passes into heat exchanger 318 and thereby provides
cooling 322 with the refrigerant at a temperature that is below
that of heat load 320. Thus, if heat load 320 is generated by a
human occupant or by electronics within an aircraft, the
temperature of the refrigerant within heat exchanger is, in one
example, 10.degree. C. Refrigerant passes to a suction accumulator
324, passes through recuperative heat exchangers 316, 314, 312, and
to a compressor 326. In one example, compressor 326 is driven by a
motor (not shown). And, although the disclosed example includes
three recuperative heat exchangers 312, 314, 316 it is contemplated
that other exemplary systems may not include all three recuperative
heat exchangers 312, 314, 316. And, the disclosed system includes
passing refrigerant through expansion device 310 and causing
two-phase or sub-critical operation, and liquefaction to occur
under the dome.
[0024] However, in one example, system 300 may be operable in a
super-critical operation. Thus, in one example, system 300 includes
an expansion machine or turbine 328. In this example, turbine 328
may be selectively operable with solenoids or valves 330, 332 that
prevent refrigerant from flowing to expansion valve 310, and
instead pass refrigerant through turbine 328. In this operation,
turbine 328 may thereby provide power to compressor 326 via a shaft
334. When the evaporating pressure reduces below the critical
pressure, the three-way valve 330 closes the path to the evaporator
and opens the path to the heat exchanger 316.
[0025] As such, system actively cools at high Mach heat
temperatures, while absorbing heat at generally ambient
temperatures, for a period of time that is not limited by a thermal
reservoir such as a fuel tank.
[0026] FIG. 4 illustrates another exemplary cooling system 400.
System 400 includes heat exchanger or gas cooler 402, heat
exchanger or evaporator 404, an expansion device 406, and an
optional expansion machine or turbine 408. System 400 includes, in
one example, solenoids or valves 410 recuperative heat exchangers
412, and a compressor 414. As with system 300 of FIG. 3, system 400
provides cooling to heat load 416 and rejects heat 418 to air that
arrives from an intake and in an aircraft operating at high Mach.
System 400 includes a compression circuit 422 in which refrigerant
passes to a compressor 424, which passes through a second heat
exchanger or gas cooler 426, which includes air 428 and to which
heat is rejected 430. Compressor 424 includes a motor 432.
[0027] In operation, heat exchangers 402, 426 reject heat 418, 430
to air 420, 428. In one example, air 420, 428 in each heat
exchanger is the same air and thus passes in one circuit to both
heat exchangers 402, 426. Compressor 424 compresses refrigerant to
a first pressure such that its temperature exceeds that of air 426
when the aircraft is traveling at Mach. Refrigerant then passes to
compressor 414, where the refrigerant is compressed to a second
pressure that is greater than the first pressure, and passes the
compressed refrigerant to heat exchanger 402, for heat rejection
418. A check valve is positioned between compressors 432, 414 to
prevent refrigerant backflow to compressor 424 in operation when
compressor 414 is not operated, such as when the heat rejection
temperature decreases, in which compressor 414 and expander 408 are
off. In such operation, heat exchanger 426 may operate as a
condenser.
[0028] Referring to FIG. 5, system 500 includes first and second
compressors 502, 504, as disclosed in system 400 of FIG. 4.
Compressor 502 is coupled to an expansion machine or turbine 506.
Intake air 508 is passed into heat exchangers or gas coolers 510,
and a heat rejection heat exchanger 512 provides heat from a heat
load 514 at approximately ambient temperature. Recuperative heat
exchanger 516 provides recuperative heat recovery. In this example,
and contrary to the systems 300, 400, only turbine 508 is included,
which thereby provides cooling for a super critical operation only.
That is, because an expansion valve or device is not included, such
system is a simplified system, and only super critical operation is
provided by system 500.
[0029] Referring to FIG. 6, system 600 includes first and second
compressors 602, 604, as disclosed in system 400 of FIG. 4.
Compressor 602 is coupled to an expansion machine or turbine 606
via a shaft 608, and to a second expansion machine or turbine 610
via a second shaft 612. Intake air 614 is passed into heat
exchangers or gas coolers 614, and a heat rejection heat exchanger
616 provides heat from a heat load 618 at approximately ambient
temperature. Recuperative heat exchangers 620 provide recuperative
heat recovery.
[0030] In operation, two-stage expansion occurs in that a first
line 622 passes refrigerant from heat exchanger 614, to a return
line 624, and to second compressor 604. Turbine 606 also provides
power to compressor 602. Second turbine 610 provides auxiliary
power to compressor 602 via shaft 612, and likewise passes
refrigerant from heat exchanger 614, to return line 624, and to
second compressor 604. In such fashion, additional expansion occurs
in comparison to, for instance, system 400 of FIG. 4, while
refrigerant passes to expansion device 626, providing cooling to
heat exchanger 616. Thus, the added expander 610 and related
recuperative heat exchangers 620 further extend the temperature
differential in the cooling system. Optionally, expanders 610 and
606 may power compressor 604; compressor 602 may be driven by an
electrical motor (not shown) or any other available prime mover.
The other option--one expander and a drive may power only one
compressor stage; the second compressor and an additional drive may
power the other compressor stage. Also, all rotating components and
a drive may be placed on one shaft.
[0031] Referring to FIG. 7, system 700 includes first and second
compressors 702, 704. First compressor 702 is coupled to a first
expander or turbine 706 via a shaft 708, and a second expander or
turbine 710 is coupled to first turbine 706 via a shaft 712. Second
turbine 710 provides auxiliary power to first turbine 706. Second
turbine 710 receives refrigerant from a heat exchanger or gas
cooler 714, and provides the refrigerant to the first turbine 706.
Refrigerant from an inlet 716 of turbine 710 passes to an expansion
device 718, which provides cooling to heat a heat exchanger 720. In
operation, power is extracted from both turbines 710, 706,
providing power to first compressor 702, while also providing
refrigerant to heat exchanger 720, while recuperative heat
exchangers 722 provide recuperative heat exchange between stages. A
heat exchanger 724 receives air and provides cooling between
compression stages 704, 702. In such fashion, the additional
expander 710 and related recuperative heat exchangers 722 extend a
temperature differential across which the cooling system may
operate, while including additional expansion capability.
[0032] All terms used in the claims are intended to be given their
broadest reasonable constructions and their ordinary meanings as
understood by those knowledgeable in the technologies described
herein unless an explicit indication to the contrary in made
herein. In particular, use of the singular articles such as "a,"
"the," "said," etc. should be read to recite one or more of the
indicated elements unless a claim recites an explicit limitation to
the contrary.
* * * * *